The Hindus have an epic called the Ramayan. The principal character in this, Ram, was said to be born in a city called Ayodhya (currently in the state of Uttar Pradesh). Way back in 1991, a fanatical Hindu organization called the VHP decided that there was once a temple to Ram at the site of the Babri Mosque and decided to demolish the mosque and build the temple there. A few minor skirmishes later, they actually carried out their threat. The Muslims (obviously) got very very angry at this and there was widespread communal rioting all over the country. While the VHP was responsible for the initial conflict, some of the worst violence in the riots was carried out by Muslim mobs.
Finally, the government cordoned off the disputed land and took possession of it. However, now, in 2002, the ****ing VHP has threatened to rebuild the temple at the disputed site. That led the Muslims to burn a train that contained people who were going to Ayodhya to build the temple. You also must consider the fact that Muslims are a minority in India (even though India has more Muslims than Pakistan) and that minorities do tend to over-react to situations that might affect them. Having said that, nothing gives people the right to burn other people alive.
This information might not be completely accurate.
As a Hindu, in order to appear impartial, I might have over-compensated a bit and not given enough stress on the fact that Muslims did play an important role in both causing and prolonging the riots.